Align PII data scrubbing in span.data and breadcrumb.data

[iker-barriocanal]

#1855 requests PII scrubbing specific fields in span.data and breadcrumb.data. Looking at data in the protocol, in breadcrumbs is undefined what the parameters are, but spans have it more defined and it's expected to follow OpenTelemetry's semantics.

In some case, such as in here, we're scrubbing breadcrumb data fields where it doesn't really make sense for an IP address to be, with the goal to remove all PII sensitive data that may have accidentally been leaked. However, this is not the case in spans.

This brings us to some questions about what the behavior should be, and what should relay do. Is there any reason not to PII scrub the whole data objects in spans and breadcrumbs? Is there any reason not to align the PII data scrubbing behavior of spans and breadcrumbs?

[iker-barriocanal]

We decided to follow what this issue suggests -- to not type all the structured data in span.data and breadcrumb.data, and perform PII scrubbing in the whole objects. We'll monitor the effects and take action accordingly.